Transcranial pituitary adenoma resection

Treatment of diseases: pituitary adenoma Indication Transcranial pituitary adenoma resection is applicable to: 1. The tumor that extends to the top of the sella is up to grade B or C. 2. The giant pituitary tumor develops on the saddle and the saddle does not enlarge. 3. The tumor block above and below the saddle is a dumbbell-shaped grower. 4. The tumor on the saddle is raised in the forward, middle, and posterior fossa (D1, D2, and D3 tumors). 5. Saddle lobulated tumor mass. Preoperative preparation 1. Endocrine examination includes a comprehensive determination of various endocrine hormones in the pituitary gland. Such as growth hormone, prolactin, adrenocorticotropic hormone, thyroid stimulating hormone, follicle stimulating hormone, luteinizing hormone and some hypothalamic endocrine hormones. 2. Imaging examination of the imaging examination of the sella and tumor. Surgical procedure After the forehead approach This is the first classical pituitary surgical approach proposed by Cushing. The frontal lobe is lifted through the dura and outside, showing the olfactory tract and optic nerve to reach the pituitary region. With the improvement of modern anesthesia techniques and surgical methods, microscope illumination can minimize the traction of the frontal lobe, thus improving the surgical outcome. It is customary to do a right frontal craniotomy (as the surgeon is used to the left hand, he can also do the left side). Some neurosurgeons tend to choose to perform surgery on the heavier side or on the side of the tumor that is more pronounced to the side of the saddle. (1) Scalp incision: The scalp incision varies according to individual habits, but the Frazier incision is used more. In recent years, due to the purpose of beauty, more authors advocate the use of a coronal incision in the hairline to avoid leaving scars on the face. 2) Open the bone flap and cut the dura mater: the bone flap of the forehead should be as low as possible, straight to the front edge of the anterior cranial fossa, but the bone flap should be designed according to the size of the frontal sinus shown by the X-ray. If the frontal sinus is opened, if the frontal sinus is accidentally sawn, it should be properly handled as usual. The dural incision is parallel to the upper edge of the iliac crest, and the inner and outer ends are cut forward and rearward to form two auxiliary incisions to form an "H" shape. The dura mater in front of the incision is sutured on the periosteum. (3) Entering the saddle area and revealing the tumor: use the brain pressure plate to gently lift the lateral side of the frontal lobe to expose the lateral fissure. The arachnoid membrane on the lateral fissure surface is torn open, the cerebrospinal fluid is aspirated, and the affected side olfactory nerve is exposed and protected as much as possible. If the operation or display is not sufficient, the olfactory beam can also be cut off. If the contralateral olfactory beam is not damaged during the operation, the patient can still retain the sense of smell. The small hemorrhage on the dura mater uses electrocoagulation to stop the blood. The sphenoid ridge is inward until the anterior bed, and the surgical side optic nerve can be seen. When lifting the frontal lobe, you must not be too hasty. You must wait for enough cerebrospinal fluid to be released to make the brain automatically retract. Do not force the brain tissue. When approaching the saddle area, carefully cover the exposed frontal lobe with cotton pads and change the serpentine brain. Open the device and continue to observe the structure of the saddle area under the operating microscope. The lateral side of the optic nerve is the ipsilateral internal carotid artery, and the inner side is the saddle septum located behind the saddle nodule. If the brain platen is slightly moved inward, the optic nerve can be seen. The surface of the above structure is generally covered with a layer of arachnoid membrane, the arachnoid membrane is torn under the microscope, the cerebrospinal fluid is further released, and the brain pressure plate is re-adjusted to make the exposure more complete. In order to avoid damage to the hypothalamic region and the cerebral artery ring and other important structures, the brain plate should not be extended to the area after the optic chiasm. Generally, the brain plate should be placed in front of the optic chiasm to expose the optic nerve and the optic chiasm. The contralateral optic nerve should not be eager to be exposed at this time, because the prominent saddle tumor often masks it and hinders the exploration. It is not difficult to expose the lateral optic nerve when the tumor block in front of the cross is mostly removed. Pituitary tumors often protrude in front of the optic chiasm, and the optic nerves on both sides are squeezed and flattened, and the optic chiasm shifts backwards. After the optic nerve and the optic chiasm are stripped, the anterior tumor is reached. In order to confirm that the tumor is substantial or cystic, and to exclude the aneurysm in the sellar region, the aspiration needle should be routinely used for puncture and aspiration before the tumor is incised. If the tumor is cystic, the brown sac fluid can be extracted and the wall of the capsule is depressed, which is more convenient for revealing the surrounding anatomical relationship and easy to operate. (4) Resection of the tumor: After the pituitary tumor is determined, the arachnoid between the optic nerves and the front of the optic chiasm should be pushed back to the top of the optic chiasm and placed close to the underside of the frontal lobe during the operation. Brain tissue, try to avoid tearing. The membrane is equivalent to covering the arachnoid above the optic chiasm of the saddle septum, and is connected backwards to the arachnoid membrane of the anterior-anterior communicating artery pool. It is as intact as possible during the operation and can reduce the chance of arterial injury. In the optic nerve between the two optic nerves away from the optic chiasm bipolar coagulation treatment of the swelled saddle septum, cut it with a long shank knife hole and cut a part of the saddle septum, which can be seen to adhere to the pituitary adenoma tissue below. The saddle septum itself is thickened and brittle, and it can be seen that it is infiltrated by tumor tissue in the pathological examination, and there are scattered tumor cell nests between the dural fibers. The gray-red tumor tissue at the incision of the saddle is often automatically ejected. If the tumor is cystic or there is bleeding in the tumor, there will be a large amount of cystic fluid and old bloody fluid overflow during the incision. It should be noted that the cotton pad is placed around the skin to reduce the contamination of the surgical field to avoid the occurrence of aseptic meningitis. If the tumor is necrotic, it can be absorbed by the aspirator. If the tumor tissue is tough, it can be removed by using a tumor-clamp or forceps. Generally, at the beginning, the tumor is more likely to bleed. At this time, the electrocoagulation of the elbow can be used to extend into the saddle to perform bipolar coagulation. Because there are no important nerves and blood vessels under the saddle (the residual normal pituitary is often displaced by the tumor to the upper back), and the tumor blood supply often comes from the saddle septum, saddle nodules and the surrounding dura mater, not only can stop bleeding after electrocoagulation, Moreover, the swelled saddle can be contracted, and the tumor body becomes smaller, which is more conducive to further operation. Generally, you can use a tumor-clamp, sputum or curette to cut the tumor, but the curette should not be too sharp. The operation should be gentle and careful. The direction of scraping is from the deep part of the back to the shallow part of the front, especially when scraping the sides. Do not scratch the inner wall of the cavernous sinus. Pituitary adenoma tissue is more fragile and softer. It is easier to remove after double-stage electrocoagulation. Sometimes it can be chopped by microscopic stripper or nasal septum stripper, and then sucked up with a suction tube. When the tumor block is cut, it is usually first from the optic nerve and the front of the optic chiasm. Then, the curved tumor is placed close to the anterior bed and protrudes into the saddle to the bottom of the saddle. The tumor is cut into the saddle and bipolar. Electrocoagulation. These operations can sometimes not be viewed directly under the operating microscope, so they must be gentle and careful, depending on the touch of the hand. The remaining tumor mass can also be removed by a suction tube. After the tumor's anterior and posterior poles are fully excised, the curved saddle and the posterior bed are visible with a curved stripper. The saddle septum gradually collapses and is separated from the optic chiasm and optic nerve. Gently pull the posterior wall of the tumor forward. Note that there are many slender blood vessels between the saddle septum and the optic chiasm. The connective saddle septum and the tumor are supplied or exported to the tumor, which can be electrocoagulated and cut off. If there is no connection between the tumor and the tumor, the blood supply artery from the upper part of the internal carotid artery bed or the anterior cerebral artery to the optic nerve and the optic chiasm may cause vision loss and hemianopia after injury, and it is difficult to recover. Generally, these blood vessels are not easy to see under the naked eye, but they are not difficult to distinguish under the operating microscope and should be protected as much as possible. This repeatedly separates and excises the swollen saddle septum and expands to the bilateral optic nerve and the tumor below the optic chiasm until the saddle compartment reveals the intertrochanteric fossa. Sometimes the tumor develops to the rear of the optic chiasm. If some of the tumor persists, the postoperative visual acuity may be poorly improved. Therefore, the cyst wall should be carefully examined and removed as much as possible. Because the saddle tumor on the pituitary tumor does not break through the saddle septum, the saddle with the overlying sulcus and the overlapping arachnoid, the saddle floor dura mater and the cavernous sinus wall on both sides, surrounded by dural tissue, no hemostasis difficult. Finally, the collapsed saddle septum can also electrocoagulate and stop the blood contraction, so that it can be opened at the outlet of the sella to prevent the postoperative visual cross-section from collapsing into the sella and affecting vision. End the operation after stopping bleeding completely. The left and right sides of the saddle are the left and right cavernous sinuses, and should not be removed excessively to avoid causing major bleeding. 2. Dural approach A surgical approach for pituitary tumors that Cushing improved and advocated in the early years. The operation and position of the bone flap were the same as before, but the dura mater was not cut after craniotomy, and the frontal lobe was lifted from the anterior cranial base to the sphenoid ridge, and the dura mater was cut 0.5 cm in front of it. Enter the dura mater, release the cerebrospinal fluid, and then enter the saddle area backwards, the other operations are the same as before. 3. Via the wing point approach Some pituitary adenomas develop to the lateral or posterior of the sella, or for the anterior optic chiasm to grow behind the optic chiasm. If the tumor cannot be displayed through the subfrontal approach, a transsphenoidal approach should be used. After craniotomy, the lower part of the forehead and the dura mater are cut in an arc or a Y shape and suspended from the periosteum near the sphenoid ridge. Close to the frontal open lateral fissure pool, separate, electrocoagulate and cut the vein injected into the sphenoid sinus, and pull the lateral part of the frontal surface of the frontal lobe to reveal the posterior part of the olfactory tract and the optic nerve. Then open the optic chiasm and the internal carotid artery pool, separate the lateral optic nerve and the internal carotid artery, release the cerebrospinal fluid, reduce the intracranial pressure, and then display the pituitary adenoma located under the optic chiasm. After resection of the tumor located near the midline, some tumors extend to the side of the saddle, involving adjacent vessels and nerves, or through the optic nerve-internal carotid artery space, the internal carotid artery-the oculomotor space, or the lateral oculomotor The outer bulge causes the gap to expand or the dura mater to bulge outward. At this time, it is necessary to carefully separate the thickened arachnoid from the corresponding gap and protect the surrounding nerves and blood vessels with a cotton pad, cut the dura mater on the surface of the tumor, and carefully use the aspirator or the tumor to pass through the corresponding neurovascular space. Intracapsular tumor resection. There is a pituitary stalk in the subarachnoid space next to the saddle, which needs to be protected. If the operation is inadvertently damaged. Will lead to diabetes insipidus. Some pituitary adenomas grow to the saddle before crossing the saddle, and are lobulated on CT and MRI images. In order to fully reveal and facilitate the resection of the tumor through the anterior approach and the internal or external approach of the internal carotid artery during the operation, a combined approach through the frontal and pterional points may be used, that is, the bone flap through the pterional approach may be enlarged inward. To the midline, the tumor blocks located in front of the optic chiasm, on the saddle and inside the temporal lobe can be removed simultaneously through the two approaches during the operation. If necessary, the anterior bed process can be removed by micro-drilling, and the cavernous sinus can be cut in the Parkinson triangle to remove the tumor that invades the cavernous sinus.